Abstract [en]

Hunting activities are responsible for the translocation and restocking of millions of animals throughout Europe, including the introduction of alien species. In a context of the growing use of game translocations and of increasing concern about the impact of biological invasions, our goal is to review the role of alien species introduced primarily for hunting purposes on the European scale. In particular, we explore: (1) the relative importance of game species in the context of alien species introductions; (2) the temporal evolution of the number of species introduced for hunting purposes; (3) the contribution of different taxa; (4) the pattern of introduced game species composition across countries (in terms of similarity), and (5) the underlying human demographic factors driving the diversity of introduced game species per country. According to our results, 24.3% of the mammals and 30.2% of the birds introduced into Europe during the last century were released primarily for hunting purposes, in total, 93 species (63 birds and 36 mammals), the most important taxa being Artiodactyls, Anseriformes and Galliformes. The species composition differed among countries, with a higher diversity of introduced game species in larger countries and in those with a higher human population density and proportion of hunters. This review stresses that hunting was a significant pathway for the introduction of invasive species into Europe in the last century. Since some of the game species introduced have had severe environmental impacts on many European regions, and introductions of non-native game species are still occurring, it is essential to improve regulations and increase public awareness regarding invasive game animals. This will help to preserve biodiversity and improve the sustainability of current hunting schemes in increasingly managed European ecosystems.

Abstract [en]

The wild boar has, over the past few decades, undergone an expansion in Europe, which may have negatively affected ground-nesting bird populations and particularly those of wading birds. The aim of this study was to evaluate predation on wadersâ nests by wild boar in Sweden, where this species has been increasing since its reintroduction. This was done by placing artificial nests in seven different study areas. A comparison was then made of predation rates of the nests placed on control plots (areas in which no wild boar were present but other predators were) and plots containing different abundances of wild boar. Contrary to our expectations, the proportion of nests predated was significantly lower in those areas in which wild boar were present, with a predation rate of 54 %, whereas the predation rate was 87.5 % in the others. The wild boar was identified as the second most important nest predator in the plots in which it was present, accounting for 18 % of the predated nests. The main predator on both types of plots was the red fox, which was responsible for 28 and 38.5 % of the predated nests on plots with/without wild boar, respectively. Interestingly, predation by badgers occurred principally in areas in which the wild boar was absent (34.5 % of the predated nests), whereas only one nest was predated by this predator in areas containing wild boar. It is not, however, possible to state whether predation by badgers was lower because of the presence of wild boar or whether this was owing to the fact that badgers do not select those particular patches because of habitat features.

Abstract [en]

Reversed size dimorphism is common in birds of prey, owls and in waders. Not much attention has been paid to the evolution of morphological characters such as wing morphology and variables related to flight agility. The aim of this study was to investigate if the morphological variables in shorebirds, related to flight performance, such as wing length, wing area, wing loading, and factors such as aspect ratio, are related to the display-flights performed by these different species of shorebirds. Data on morphological variables, e.g. body mass, wing length, wing area etc. was collected at the British Museum of Natural History, London, UK.

Data on behavioral variables, e.g. duration of a display flight or height of display flight was extracted from the published literature. There was a significant difference in wing length dimorphism (t = 2.51, p= 0.0402), when comparing between species within the same genus that had higher versus lower level of flight performance. There was also a significant difference in wing area dimorphism (t = 2.84, p= 0.025), for higher versus lower level of flight performance. However, there was no such difference for weight dimorphism, nor for tarsus dimorphism, or for wing loading or aspect ratio, when comparing between species for higher versus lower level of flight performance. Further analyses will be presented and a suggestive explanation for the evolution of reversed sexual dimorphism will be discussed at the congress. The hypotheses for increased food- or incubation efficiency is with several arguments irrelevant to shorebirds (which will be discussed).

Abstract [en]

A sustainable fishery in the Baltic and Bothnian Seas requires the development and introduction of fishing gear which fishes selectively and at the same time excludes raiding seals. The purpose of this study was twofold: firstly to test and evaluate rigid grids as a method for retaining only larger herring in a pontoon trap, and secondly to analyze which factors were influencing the selection process. The results demonstrate that it is indeed possible to sort herring by size in a pontoon fish chamber. The efficiency of excluding undersized herring was at best 27%, using a selection grid covering just over 0.1% of the fish chamber wall. The factors which have most effect on the selection were the quantity of fish in the trap, the season of the year, the time of day and the presence of seals. (C) 2010 Elsevier B.V. All rights reserved.

Österdal, Henrik

Abstract [en]

The Swedish moose population has during the last 60 years been going through rather drastic changes in numbers. Recently there also seemed to have been a shift towards males with less and less developed antlers, which is an important problem for the moose population breeding. The aim with the present study was to study how antler size in the moose is related to age, body mass and population density. Information on the antler and body mass characters was obtained from 425 males that were shot during the annual moose hunting in October between the years 1999-2006. Age and body mass were the variables that explained most of the variation in antler size in this study. A residual of antler points over age, demonstrated a positive correlation between residuals and carcass, such that males with larger antlers for their age, was on average heavier than other males. There was also a significant negative correlation between population density and carcass. The high mortality rate of older males have lead to that few males reach an age where the horns are fully developed and the age distribution has moved to younger ages. As a consequence of this fact the males start to reproduce at younger ages. As the rutting behaviour is a very energy demanding activity, the younger male’s body growth will be constrained and there will be a large cost to come in rutting stage early. As the percentage of males and male age is having an impact on the reproduction of the population, this is an important problem which should be considered in order to give the right prerequisites for a more productive population of moose with big males that have well developed horns.

Abstract [en]

El Hondo is a key area for marbled teal and white-headed duck. We present Pb, Cu, Zn, Se, and As data for bone and liver in birds found dead between 1996 and 2001. Several metals were higher in adult white-headed ducks than in marbled teal. They were higher in female than in male white-headed ducks, and did not differ with sex in marbled teal, but did by age. Lead in liver of adults was influenced by Pb shot ingestion, which was detected in 21% of marbled teal and in 71% of white-headed duck. No marbled teal had liver levels indicative of Pb poisoning, while 86% of white-headed ducks did. Selenium, Zn, and Cu were elevated in 13%, 7%, and 39% of birds, respectively. Whilst Pb shot poses the greatest threat to these species, further work should assess exposure via plants, invertebrates, water, and sediments for other metals, and investigate possible sub-lethal effects.

Doumandji, Salaheddine

Abstract [en]

Clutch size is an important life history trait and factors such as nest predation and food availability can both be of crucial importance for its variation in nature. The aim of the present study was to evaluate the effects of extra food on clutch size, laying date and hatching success in the White stork Ciconia ciconia. Three different colonies of White stork were studied over a three-year period where there was difference in both food availability and precipitation. This study demonstrated that an extra food supply during the pre-laying period had a positive effect on clutch size - nests with extra food had a larger clutch size. There was also an advance in laying date and a higher hatching success in nests with access to extra food. In addition to food supply, clutch size was independently affected by rainfall, which suggests that parents additionally also were sensitive to other external cues than to the extra food. Furthermore, this study also suggests that an extra food during the incubation period could probably help the parents to solve the conflict between incubation behaviour and minimizing the time off the nest, i.e. increasing nest attentiveness in nests with extra food.